How many countries were participating in world war 1?

World War I involved over 30 countries, primarily divided into two main alliances: the Allies and the Central Powers. The major Allied Powers included countries like France, the United Kingdom, Russia, Italy, and the United States, while the Central Powers consisted mainly of Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria. The war lasted from 1914 to 1918 and had a profound impact on the geopolitical landscape of the world.